UV photon assist ionization for low temperature plasma

Abstract

A new type plasma Source has been developed for the generation of low temperature plasma. The plasma generation process consists of two steps, the generation of metastable neutral gas by injecting a low energy electron beam (the thermionic Source) and the ionization of the metastable neutral gas by application of a UV light source. The key characteristic of this plasma source is the capability of producing extremely low temperature plasma. In the experiment, the filament heating current is 6.5 A and the electron acceleration voltage varies from 16 V to 25 V. Plasma parameters are measured by a single Langmuir probe. The plasma density increases 100% from 4.5 x 10(9) cm(-3) to 9.8 x 10(9) cm(-3) in Ar 30 mTorr when the neutrals excited by the e-beam are exposed to the UV light. However, the electron temperature is still low, i.e., similar to 0.5 eV. A similar result is observed in the case of Xe. (c) 2005 Elsevier B.V. All rights reserved.